Phonovision not digital?

[Viewmaster]

There's discussion on other threads about storing digitally......
But as true NBTV believers in the faith(!) shouldn't we be designing and building cutter heads and obtaining shellac discs to record NBTV onto records? Phonovision!

Recording onto CD is so clinical and lacks all the excitment of such things as neeedle sharpening on playback and accidentally hitting the reproducer's arm...
....sccccreeeeeeeeech!

Getting the groove modulation correct. Having two tracks, two cutting heads and two playback reproducers, one for vision and the other for audio....just think about all those Phonovision problems and what we are all missing with our clinical CDs.

Albert.

[Stephen]

There's discussion on other threads about storing digitally......
But as true NBTV believers in the faith(!) shouldn't we be designing and building cutter heads and obtaining shellac discs to record NBTV onto records? Phonovision!

Yes, indeed! I want my Phonovision!

Recording onto CD is so clinical and lacks all the excitment of such things as neeedle sharpening on playback and accidentally hitting the reproducer's arm...
....sccccreeeeeeeeech!

And there is something almost mesmerising about watching the cut thread collect on the surface of an acetate recording blank.

Getting the groove modulation correct. Having two tracks, two cutting heads and two playback reproducers, one for vision and the other for audio....just think about all those Phonovision problems and what we are all missing with our clinical CDs.

Actually, Mr. Baird describes a composite single audio/video groove as one possible embodiment in his Phonovision patent. The video channel is hill-and-dale, the audio channel is lateral. See page 3, column 1, lines 41 through 46 of British Patent 289,104, filed 15 October 1926, in the Patent and Articles section of the forum.

A "stereo" recording lathe that includes the 78 rpm speed could do this. It would only be necessary to reverse the leads for one of the channels on the recording head to convert it from the compatible 45-45 system to hill-and-dale plus lateral. I would that imagine that with 12 inch blanks a frequency range of 10 to 15 kHz would not be out of the question as long as the minimum inner radius remains rather large. 16 inch transcription blanks might do even better, perhaps up to 20 kHz or the limit of the recording head. Likewise, an ordinary stereo gramophone with the 78 rpm speed and one of the playback channel leads reversed would be a fine audio/visual Phonovision reproducer.

I do not know where one would get a stereo recording lathe nowadays, much less suitable "standard groove" cutting styii and aluminium base, acetate coated recording blanks. I have a box of them in my garage, but they are so old they may not even provide a decent cut. Folker mentioned that some sort of 78 rpm cutting system is currently available for a princely sum, but I have not been able to find anything about it.

[DrZarkov]

I was talking about a cutting system for 33 rpm records, available for about 2000 EUR for my Technics record-player. If we want to have it affordable I suggest to use cylinder records, a phonograph (in original/british meaning of the word) turned for NBTV, a "Visiograph" system. It is much easier to make your own cylinder recordings than disc recordings. The advantages: The length of the grove does not change from the beginning to the end, that means constant quality (at a 12 inch disc the quality gets worse to the middle of the record, maybe viewable with NBTV.

Very interesting, Walter Bruch, the inventor of the PAL-system experimented with phonographs, he built an electronic pick-up system for it for restoring old cylinders. He wrote a book about it, I found it years ago in a library. I hope they still have it to make some copies.

[Stephen]

If we want to have it affordable I suggest to use cylinder records, a phonograph (in original/british meaning of the word) turned for NBTV, a "Visiograph" system. It is much easier to make your own cylinder recordings than disc recordings. The advantages: The length of the grove does not change from the beginning to the end, that means constant quality (at a 12 inch disc the quality gets worse to the middle of the record, maybe viewable with NBTV.

I always thought that cylinders were the way to go. My turn of the 20th century Edison "Home" machine has a recording head attachment. The recording quality from beginning to end is consistent, although mediocre, and there is no possibility of the recording horn introducing any gamma factor. I need to find some more blank wax cylinders. Two minutes of recording does not go very far.

[Klaas Robers]

This discussion reminds me to a related problem.

You all still know that grammophone records are played from the outer edge to the centre. But why this way?

CD's are played from the centre outwards. Much easier, starts at the same diametre, regardless the size of the disc, 12 cm, 8 cm of whatever. All optical discs do: the old Laservision, DVD, Blu-ray. But why grammophone records not?

[Stephen]

This discussion reminds me to a related problem.

You all still know that grammophone records are played from the outer edge to the centre. But why this way?

CD's are played from the centre outwards. Much easier, starts at the same diametre, regardless the size of the disc, 12 cm, 8 cm of whatever. All optical discs do: the old Laservision, DVD, Blu-ray. But why grammophone records not?

The outside-in format never made sense to me either. Actually, the original 33-1/3 rpm discs developed by Western Electric in 1926 for the "Vitaphone" sound films are 16 inch with and an inside-out, hill-and-dale recording format. Radio broadcasters later adopted this system for their transcription discs, so most surviving radio programmes from the 1930s and 1940s are in this format.

The other nice thing about recording inside out is that you do not have to worry about the cutting thread wrapping around the cutting stylus. It will simply collect in the centre of the disc. With the outside-in format, you either have to vacuum up the thread or brush it inwards as the stylus cuts the groove to avoid having the thread getting tangled in the stylus. Both of these methods can transfer noise to the recording and failure of either results in a ruined disc. In the distant past I lost a number of recordings due to faulty thread collection.

[Andrew Davie]

http://www.vinylvideo.com/

[Stephen]

http://www.vinylvideo.com/

This is good, Andrew. Now we have to work on ShellacVideo, or perhaps CylindricalVideo, if we opt for cylinders.

[Andrew Davie]

http://video.google.de/videoplay?docid= ... 4651871591

http://video.google.de/videoplay?docid= ... 8186283673

http://video.google.de/videoplay?docid= ... 6246849951


The above will also lead you to a number of other interesting clips. Picture quality and resolution looks surprisingly good!

http://www.youtube.com/watch?v=7qQi1LoQowE

The above a pretty cool implementation of faceted mirrors to give a moving image, too!


Cheers
A

[Stephen]

I am just amazed at what VinylVideo is getting out of an LP. We should be able to do as well with ShellacVideo.

[DrZarkov]

I found it less amazing how much they ask for it...

[Viewmaster]

I found it less amazing how much they ask for it...

I can afford the T shirt.

Well, it seems there is great interest in a cylinder phonovisor and enough talent on this forum to design and build it.....I look forward to seeing one at next years Loughboro conference.....or the year after.

If I ever built one I would favour a disc machine as it would look more interesting whilst running.

First problem to be solved is the inter coupling of the Nipkow camera disc to the cylinder rotation and the grooves per picture frame protocol to be adopted. Direct coupling to Nipkow at 12.5 revs per sec is too fast for cylinder if recording time is to be for some minutes.

How fast did the old cylinders run?

Of course, this machine must really have old valves as amplifiers for the head and playback.....preferably bright emitters!
Transistors and ICs are banned.
Albert.

[DrZarkov]

the original brown cylinders from Edison run at 120 rpm, the black at 160 rpm (2 minute) and the blue amberol at 80 rpm (4 minutes). I suggest the Bell Tainter system with wax covered cardboard cylinders, because they are easy to make. 125 rpm would make sence, or a bigger cylinder (like the old "concert cylinders"), but with 60,25 rpm.

I wonder if "Fimo", a clay which becomes hard like vinyl after heating it would be a good material for a cylinder.

Bruch used a common stereo pickup from an old record player for his phonograph. It works fine with hill and dale written cylinders, but would work of course with "stereo" cylinders, too. For writing we would have to construct our own device. There is a company in the Blackforest (I have to look up the name) still making stylus (styli?) at customer request for exotic hardware like phonographs.

[Steve Anderson]

First problem to be solved is the inter coupling of the Nipkow camera disc to the cylinder rotation and the grooves per picture frame protocol to be adopted. Direct coupling to Nipkow at 12.5 revs per sec is too fast for cylinder if recording time is to be for some minutes.

How fast did the old cylinders run?

Now this is an area where I do have an interest in the mechanical side of things. The 10" 78RPM record had a linear velocity at the outermost groove (say 4.5" from the centre) of 933mm/sec. The 7" 45RPM single of 360mm/sec, and the 33.3RPM 12" disc of 487mm/sec, near the outermost grooves which were where the best fidelity was possible.

So in keeping with the above a linear cylinder velocity of 500mm/sec would seem reasonable. At 750RPM this translates to a cylinder diameter of 12.7mm (or half an inch), if using the same shaft to drive the disc/drum as the cylinder player, a little too small I think. (Please check my maths...it's been a long day).

So some form of gearbox would need to be introduced to reduce the RPM of the cylinder and enlarge its diameter to more resonable dimensions and give sensible playing time.

A reduction ratio of 8:1 would result in a cylinder rotating at 1.56 revs/sec, 93.75RPM and a diameter of around 100mm. (Please check my maths again).

Now, what I don't know is how the modulation depths were derived, i.e. what is the pitch of the spiral/helix around the cylinder. It's somewhat of a comprimise between signal-to-noise ratio, maximum excursion of the cutting and playback stylii and playing duration.

The overall advantage here is that with a mechanical index (a notch) on the cylinder the headache of syncronisation goes away.

Of course, this machine must really have old valves as amplifiers for the head and playback.....preferably bright emitters!
Transistors and ICs are banned.
Albert.

Albert, even though I'm a self-confessed hypocrite, I'm on your side here. I think a cut-off date of 1950 would suit me fine. If you couldn't buy it retail (excludes R&D projects) then you can't use it. I'll conceed 1% resistors and vastly smaller caps, but that's about it.

Steve A.

[DrZarkov]

For the signal we don't need much more than a 1 valve preamplifier, the rest does the monitor. The question is, how do we do the synch-signal? Written in the groove (then we don't have to care much about the speed of the cylinder, as long as the quality is good enough, and recording is as fast as playback), or generated by an aperture-disc or stroboscope connected to the cylinder?